Water-based liquid treatment for aluminum and its alloys

ABSTRACT

A chromium-free water-based surface treatment liquid which contains from 0.01 to 50 g/l of a total of dissolved manganic acid, permanganic acid, and salt(s) thereof and from 0.01 to 20 g/l of a total of dissolved titanium compounds and has a pH of from 1.0 to 6.0 reacts rapidly with aluminum and aluminum alloy surfaces to deposit thereon a protective coating that does not contain hexavalent chromium and has excellent corrosion resistance and paint film holding properties.

FIELD OF THE INVENTION

This invention concerns a novel liquid for the surface treatment ofaluminum or aluminum alloy materials for imparting superior corrosionresistance and paint film holding properties to such surfaces. Fields inwhich the invention can be used with particular effectiveness includethe surface treatment of aluminum heat exchanger fins and aluminum alloycoils and sheets.

RELATED ART

The liquids used for the surface treatment of aluminum and aluminumalloy materials can be broadly classified as being of the chromate typeor the non-chromate type. Chromic acid chromate forming treatmentliquids and phosphoric acid chromate forming treatment liquids can becited as typical examples of chromate type treatment liquids.

Chromic acid chromate forming treatment liquids have been in practicaluse since about 1950 and today they are widely used for the surfacetreatment of heat exchanger fins, aluminum wheels, building materialsand aircraft materials. These chromic acid chromate forming treatmentliquids contain chromic acid and fluoride as a reaction promotor asessential components, and a formed film which contains some hexavalentchromium is obtained on the metal material surface.

Phosphoric acid chromate forming treatment liquids are an inventiondisclosed in U.S. Pat. No. 2,438,877; they contain chromic acid,phosphoric acid and hydrofluoric acid as the main components, and aformed film which has hydrated chromium phosphate as the main componentis obtained on the metal material surface. No hexavalent chromium isincluded in this formed film. Therefore these materials are being widelyused at the present time as a paint undercoating treatment for thebodies and lids of beverage cans.

Although a formed film which has been obtained with such a surfacetreatment liquid of the chromate type has excellent corrosion resistanceand paint film holding properties, harmful hexavalent chromium iscontained in the treatment liquid and so the use of a treatment liquidwhich does not contain hexavalent chromium at all is desirable in termsof avoiding environmental problems.

The method disclosed in Japanese Unexamined Patent Application (Kokai)52-131937 can be cited as a typical invention of a non-chromate typesurface treatment liquid. This surface treatment liquid is an acidicaqueous coating solution, with a pH from about 1.5 to about 4.0, whichcontains zirconium or titanium or a mixture of the two, phosphate andfluoride. A formed film which has zirconium or titanium oxide as themain component is obtained on the metal surface when a metal surface istreated with such a surface treatment liquid. The non-chromate typesurface treatment liquids do have the advantage of not containinghexavalent chromium, and they are widely used at present for the surfacetreatment of drawn-and-ironed (hereinafter usually abbreviated as “DI”)aluminum cans, but there is a disadvantage in that the corrosionresistance of the film which is formed is not as good as that of achromate film.

Furthermore, the method of treatment disclosed in Japanese UnexaminedPatent Application (Kokai) 57-41376 involves the surface treatment ofthe surface of aluminum, magnesium, or an alloy of these metals, usingan aqueous solution which contains one type, or two or more types, oftitanium salt or zirconium salt and one type, or two or more types, ofimidazole derivative.

The corrosion resistance of the film, according to the illustrativeexamples, is such that there is no rusting in 48 hours when tested inaccordance with JIS-Z-2371. However, although this performance wassatisfactory 15 years ago, it cannot be said to be truly adequate at thepresent time. This specification also indicates that oxidizing agentssuch as nitric acid or hydrogen peroxide or potassium permanganate canbe used as well, being added in amounts, calculated as compounds, offrom 0.01 to 100 grams per liter (hereinafter usually abbreviated as“g/l”), but there are no illustrative examples of oxidizing agents suchas potassium permanganate.

Furthermore, a method of surface treatment whereby a formed film isobtained on the surface of an aluminum material with an aqueous solutionwhich contains potassium permanganate or potassium manganate, or both ofthese materials, and mineral acid (HNO₃, H₂SO₄, HF), alkali (KOH, NaOH,NH₄OH), neutral fluoride (KF, NaF), acidic fluoride (NH₄HF₂, NaHF₂,KHF₂), silicofluoride (MnSiF₆, MgSiF₆) and the like has been disclosedin Japanese Unexamined Patent Application (Kokai) H8-144063. However, acorrosion resistance similar to or better than that of a chromate filmcannot be anticipated when long term corrosion resistance tests arecarried out with formed films which had been obtained with this liquid.

As indicated above, the problems of the corrosion resistance of the filmwhich is formed and the treatment of the waste surface treatment liquid,for example, remain when the aforementioned conventional non-chromatetype surface treatment liquids are used. From this viewpoint, thenon-chromate type surface treatment liquids are hardly being used at allat the present time on the surface treatment part of manufacturing linesfor aluminum based metal coils and sheets and the aluminum fins for heatexchanges, where especially good corrosion resistance is required.

Hence, at the present time the prior art does not provide any surfacetreatment liquid, for aluminum or aluminum alloy materials, which doesnot contain hexavalent chromium, which has excellent effluent treatmentproperties and with which a formed film which has excellent corrosionresistance and paint film adhesion properties is obtained.

PROBLEM TO BE SOLVED BY THE INVENTION

The present invention is intended to resolve the problems describedabove which are associated with the prior art, and in practical terms itis intended to provide a surface treatment liquid with which a filmcomprising specified metals can be obtained on an aluminum or aluminumalloy material surface and which can impart excellent corrosionresistance and paint film holding properties.

SUMMARY OF THE INVENTION

It has been discovered that it is possible to obtain a formed film whichhas excellent corrosion resistance and paint film adhesion properties onan aluminum or aluminum alloy surface by using a surface treatmentliquid of pH from 1.0 to 6.0 which contains a prescribed amount ofpermanganic acid or one or more of its salt(s) and a prescribed amountof at least one type of compound selected from among water solubletitanium compounds and water soluble zirconium compounds, and theinvention is based upon this discovery.

More particularly, a surface treatment liquid of this invention is awater-based liquid which contains from 0.01 to 50 g/l of permanganicacid and/or its salts, and from 0.01 to 20 g/l of at least one compoundselected from among water soluble titanium compounds and water solublezirconium compounds, and which has a pH of from 1.0 to 6.0.

DETAILED DESCRIPTION OF THE INVENTION

In this invention it is important that a complex film comprisingcompounds of two or more metal elements and which includes manganese,such as manganese and titanium, manganese and zirconium or manganese,titanium and zirconium, is formed, and the corrosion resistance of theformed film which is obtained is improved by this means.

Permanganic acid and/or its salts can be used to introduce the acid(s)and/or salt(s) thereof into a surface treatment liquid of thisinvention, and no narrow limitation is imposed upon the particular typeof material used. The total concentration of permanganic acid andsalt(s) thereof must be within the range from 0.01 to 50 g/l, andpreferably is within the range from 0.05 to 20 g/l. A formed film may beobtained even if the concentration of permanganic acid and/or salt(s)thereof is less than 0.01 g/l, but this is undesirable, because thecorrosion resistance and paint film adhesion properties of any such filmare poor. A good formed film is obtained with a concentration of morethan 50 g/l, but the properties of the film are no better than with 50g/l, the cost of the treatment liquid is increased, and this iseconomically wasteful.

One type, or two or more types, of compound selected from among thesulfates, oxysulfates, acetates, ammonium salts and fluorides, forexample, of titanium and zirconium can be used to introduce the watersoluble titanium compound or water soluble zirconium compound into asurface treatment liquid of this invention, and no limitation is imposedon the type of compound, provided that it is water soluble. Furthermore,the amount included must be within the range from 0.01 to 20 g/l, andpreferably within the range from 0.1 to 3 g/l. A formed film can beobtained even if the water soluble titanium compound or water solublezirconium compound content is less than 0.01 g/l, but this isundesirable since the corrosion resistance of any such film is poor. Agood formed film is obtained with more than 20 g/l, but the propertiesof the film are no better than with 20 g/l, the cost of the treatmentliquid is increased and this is economically wasteful.

The pH of a surface treatment liquid of this invention must be withinthe range from 1.0 to 6.0 and is preferably within the range from 2.0 to5.0. Excessive etching of the metal material surface occurs at a pH lessthan 1.0 and irregularities arise in the appearance; this isundesirable. Furthermore, if the pH exceeds 6.0, then it may becomedifficult to obtain a formed film which has excellent corrosionresistance, and there are cases where problems arise with the stabilityof the liquid, because the metal ions which are contained in thetreatment liquid are likely to form a precipitate; this is undesirable.Acids such as nitric acid, sulfuric acid, phosphoric acid, hydrofluoricacid and fluorosilicic acid and alkalies such as sodium hydroxide,sodium carbonate, potassium hydroxide and ammonium hydroxide can beused, as required, when adjusting the pH of a surface treatment liquidof this invention to within the range from 1.0 to 6.0.

Moreover, in those cases where the metal substrate in this invention isan aluminum alloy which contains copper, iron, magnesium or the like,the stability of the treatment liquid is markedly reduced by metal ions,such as copper and/or magnesium ions, derived from the metal componentwhich are dissolved in the surface treatment liquid, so that in thisinstance organic acids such as gluconic acid, heptogluconic acid, oxalicacid, tartaric acid, organophosphonic acid, ethylenediamine tetra-aceticacid and the alkali metal salts of these acids may advantageously beadded as chelating agents to chelate these alloy component metals.

Furthermore, tungstic acid, molybdic acid and their salts, and watersoluble organic peroxides such as tert-butylhydroperoxide, which has thechemical formula (CH₃)₃C—OOH, can be used conjointly in order to promotethe formation of a film in this invention.

The formed films which are obtained by the method described above arecomprised of manganese and at least one species selected from amongtitanium and zirconium as structural components, and the ratio by weightof Mn/(Ti+Zr) is preferably within the range from 0.1 to 20.0:1.0, andmore preferably within the range from 0.2 to 5.0:1.0. The mass per unitarea of the formed film of these metals independently preferably is from5 to 500 milligrams per square centimeter of surface coated (hereinafterusually abbreviated as “mg/m²”).

The manganese, titanium and zirconium which are the structuralcomponents of a formed film of this invention are unlimited in terms ofthe chemical characteristics with which they are present in the film,and they may be present, for example, as the metals, oxides orphosphates.

Next, the method of treating aluminum or aluminum alloy material using asurface treatment liquid of this invention will be described.

A surface treatment liquid of this invention is preferably used in aprocess sequence such as follows below:

(1) Surface Clean: Degreasing (with an acid, an alkali or a solventsystem)

(2) Water rinse

(3) Surface treatment with a treatment liquid of the invention

(4) Water rinse

(5) Rinse with deionized water

(6) Drying.

Independently, a surface treatment liquid of this invention ispreferably brought into contact with the surface of the aluminum oraluminum alloy material at a temperature of from 20 to 80° C. for aperiod of from 1 to 120 seconds. At contact temperatures below 20° C.,the reactivity between the treatment liquid and the metal surface islow, so that a good formed film is not usually obtained, and if thetemperature exceeds 80° C., a formed film is obtained but the energycosts are high and this is economically wasteful. Furthermore, reactionis usually inadequate with a treatment time of less than 1 second, sothat a formed film which has excellent corrosion resistance is notobtained. On the other hand, no improvement in the corrosion resistanceand paint film adhesion properties of the formed film obtained have beenseen if the contact time exceeds 120 seconds.

Moreover, any method of contacting the substrate being treated with thesurface treatment liquid, such as an immersion method or a sprayingmethod, can be used in this invention.

The amount of formed film deposited on the surface of an aluminum oraluminum alloy material by means of the method of this inventionpreferably contains from 5 to 300 mg/m² of manganese and from 3 to 100mg/m² of titanium, zirconium, or both. If the amount of depositedmanganese is less than 5 mg/m², the corrosion resistance and paint filmadhesion properties of the formed film obtained usually are inadequate,and if this amount exceeds 300 mg/m², it is undesirable in terms of theirregularity of the appearance of the formed film which is obtained.Furthermore, if the amount of deposited titanium and/or zirconium isless than 3 mg/m², the corrosion resistance of the formed film which isobtained is usually inadequate, and if the amount exceeds 100 mg/m², aformed film which has excellent corrosion resistance, but one which isno better than that obtained at 100 mg/m², is obtained; this iseconomically wasteful.

Aluminum or aluminum alloy materials which may be surface treated bymeans of the method of this invention include pure aluminum and aluminumalloys, and the aluminum alloys include alloys such as Al—Cu, Al—Mn,Al—Mg and Al—Si alloys, for example. Furthermore, no limitation isimposed upon the shape or dimensions of the aluminum or aluminum alloymaterial with which the method of the invention is used, and the formsinclude sheets and various moldings, for example.

Illustrative examples, which are not to be construed as limiting theinvention, are described along with comparative examples below, and theeffect of a surface treatment liquid of this invention is described inmore detailed terms.

Substrate Used in the Tests

Al—Mn alloy sheet according to Japanese Industrial Standard (hereinafterusually abbreviated as “JIS”) 3004 was used. Dimensions: 150 mm×70 mm,Thickness 0.2 mm.

Treatment Conditions

The treatment was carried out in the process order(1)→(2)→(3)→(4)→(5)→(6) as detailed below, and a surface treated sheetwas obtained.

(1) Degreasing: (60° C., 60 seconds, immersion method) A 3% aqueoussolution of a commercial alkaline degreasing agent (registered tradename: FineCleaner® 315, manufactured by the Nihon Parkerizing Co.) wasused.

(2) Water rinse (Normal ambient human comfort temperature, 10 seconds,spray method)

(3) Forming Treatment (immersion method)

The substances used as the sources of manganese, zirconium, and titaniumand for pH adjustment in Examples 1 to 5 and Comparative Examples 1 to 4are shown in Table 1, which also contains identifying letters andnumbers that are used as abbreviations in the next table.

TABLE 1 Component Source Water Soluble a: Manganese sulfate (i.e.,MnSO₄.H₂O) Manganese b: Potassium manganate (i.e., K₂MnO₄) Compound c:Potassium permanganate (i.e., KMnO₄) Water Soluble A: 40% Fluorotitanicacid (i.e., H₂TiF₆) solution in water Titanium B: 24% Titanium sulfate(i.e., Ti(SO₄)₂) solution in water Compound Water Soluble i: 20%fluorozirconic acid (i.e., H₂ZrF₆) solution in water Zirconium ii:Ammonium fluorozirconate (i.e., (NH₄)₂ZrF₆) Compound pH Adjusting I:67.5% nitric acid (i.e., HNO₃) solution in water Agent II: 40%fluorosilicic acid (i.e., H₂SiF₆) solution in water III: 25% ammonia(i.e., NH₃) solution in water

Surface treatment was carried out with the composition and under thetreatment conditions shown in Table 2, in which the amount of eachsubstance indicated in a treatment liquid composition column in Table 2by an identifying letter or number from Table 1 is the amount of thecorresponding pure active ingredient as shown in Table 1.

Also, the surface treatment conditions for Comparative Examples 5 to 7are indicated below.

(4) Water Rinse (Normal ambient human comfort temperature, 30 seconds,immersion method)

(5) Rinse with Deionized Water (Normal ambient human comforttemperature, 30 seconds, immersion method)

(6) Heating and Drying (80° C., 3 minutes, hot forced air oven)

TABLE 2 COMPOSITION AND PROCESS CONDITIONS AND RESULTS OF EVALUATIONTESTS Treatment Composition of the Forming Treatment Liquid (g/l)Conditions Mn Ti pH Tem- Exam- Source(s) Source Zr Adjust- pera- Time,ple and and Source and ing ture, Sec- Number Amounts Amount Amount AgentpH ° C. onds 1 a 1.0 - - i 0.3 III 4.5 60 60 b 10.0  c 0.5 2 b 3.0 A0.9 - - - 2.6 35 120  c 3.0 3 c 5.0 B 0.8 - - I 2.4 50 30 4 c 5.0 - - i0.1 II 3.5 60 60 5 a 1.0 A 0.1 ii 0.1 III 3.5 70 10 c 1.0 Comp.1 c10.0  - - - - I 2.0 60 60 Comp.2 - - - - i 0.3 - 3.0 60 60 Comp.3 b10.0  A  0.008 - - I II 3.8 60 60 Comp.4 a  0.93 A 1.0 - - III 3.0 60 60Comp.5 - - - - - - - 2.9 10 30 Comp.6 - - - - - - - 1.6 40 60Comp.7 - - - - - - - 1.6 50 20 Corro- Film sion Adhesion Mass, Resist-Proper- Ratio by mg/m² ance ties, % of Weight, of SST, Squares ExampleFilm Contents, mg/m² of Mn: (Mn + Ti + 1000 Remain- Number Mn Ti Zr Cr(Ti + Zr) Zr) Hours ing 1  5 - 30 - 0.17 35 ⊚ 100  2 110  80 - - 1.38190  ⊚ 98 3 28 12 - - 2.33 40 ∘ 96 4 68 -  8 - 8.50 76 ∘ 99 5 60 12 45 -0.88 107  ⊚ 100  Comp. 1 55 - - - n.m. n.m. Δ 98 Comp. 2 - - 45 - n.m.n.m. X 75 Comp. 3 48  3 - - 16.00  51 Δ 99 Comp. 4  3 38 - - 0.08 41 X82 Comp. 5 - - 15 - n.m. n.m. X 100  Comp. 6 - - - 170 n.m. n.m. ⊚ 99Comp. 7 - - -  70 n.m. n.m. ∘ 100  Abbreviations and Other Note forTable 2 “Comp” means “Comparison”; “n.m.” means “not measured”. A hyphenentry in a cell indicates that none of the material in the columnheading for the cell in question was deliberately added.

COMPARATIVE EXAMPLE 5

A 7% aqueous solution of a commercial zirconium phosphate based surfacetreating agent (registered trade name: Arochrome® 713, manufactured bythe Nihon Parkerizing Co.) was used for the forming treatment. Theliquid was used at a temperature of 40° C. for a contact time of 60seconds by immersion, to treat the aforementioned Al—Mn based alloysheet.

COMPARATIVE EXAMPLE 6

A 7% aqueous solution of a commercial chromic acid chromate formingtreatment agent (registered trade name: Alchrome® 713, manufactured bythe Nihon Parkerizing Co.) was used for the surface treatment. Theliquid was used under the same process conditions to treat the sameAl—Mn based alloy sheet as in Comparative Example 5.

COMPARATIVE EXAMPLE 7

A 3% aqueous solution of a commercial phosphoric acid-chromate formingtreatment agent (an aqueous solution of a mixture of 4% of a productwith the registered trade name Alchrome® K702SL, and 0.3% of a productwith the registered trade name Alchrome® K702AC 0.3%, both manufacturedby the Nihon Parkerizing Co.) was used for the surface treatment. Theliquid was used at a temperature of 50° C. for a contact time of 20seconds, using a spray method, to treat the same type of Al—Mn basedalloy sheet as in Comparative Examples 5 and 6.

Methods of Evaluation

(1) Amount Deposited

The amounts of Mn, Ti, Zr and/or Cr in the films were measured usingfluorescence X-ray diffraction apparatus.

(2) Corrosion Resistance

A salt water spray test in accordance with JIS Z-2371 was used toevaluate corrosion resistance. The state of corrosion of the surfacetreated sheet after salt water spraying for 1,000 hours was assessedvisually and is reported by using the following symbols:

⊚: Corroded area less than 10%;

∘: Corroded area at least 10% but less than 50%;

Δ: Corroded area at least 50% but less than 90%; and

X: Corroded area at least 90%.

(3) Paint Film Adhesion Properties

An epoxy-phenol based can-lid paint was applied to a paint filmthickness of 5 micrometers on the surface of the Al—Mn based alloysheets which had been surface treated under the conditions of Examples 1to 5 and Comparative Examples 1 to 7, and was then baked for 3 minutesat 220° C. Next, 100 squares of width 2 mm were cut with a scriber inthe middle part of the painted sheet and the sheets were immersed indeionized boiling water for 60 minutes. Then, the painted sheet wasdried and subjected to cellophane tape peeling test, and the paint filmadhesion properties were evaluated by means of the remaining number ofsquares which had not peeled off with the tape. In this test, a largernumber of squares remaining signifies superior paint film adhesionproperties and a number of 98 or above remaining indicates performancewhich is satisfactory for even very demanding practical uses. Theresults of the evaluations are shown in Table 2.

It is clear from Table 2 that the formed films obtained with thetreatment liquids of this invention had similar corrosion resistance tothose obtained with a commercial chromic acid chromate or phosphoricacid chromate treatment, and that excellent corrosion resistance can berealized by forming a complex film with appropriate amounts of Mn andTi/Zr.

Benefits of the Invention

As is clear from the description above, it is possible to obtain aformed film which has excellent corrosion resistance and paint filmadhesion properties and which does not contain hexavalent chromium byapplying a surface treatment liquid of this invention to an aluminum oraluminum alloy substrate. Hence, the aluminum or aluminum alloy materialsurface treatment liquids of this invention are very effective inpractice.

What is claimed is:
 1. A liquid composition suitable for the surfacetreatment of aluminum and aluminum alloy substrate surfaces, saidcomposition having a pH value in a range from 1.0 to 6.0 and comprisingwater and the following components (A) and (B): (A) a concentration offrom 0.01 to 50 g/l of solute molecules selected from the groupconsisting of permanganic acid and its salts; and (B) a concentration offrom 0.01 to 20 g/l of solute molecules selected from titanium compoundsand zirconium compounds.
 2. A composition according to claim 1, whereinthe concentration of component (A) is from 0.05 to 20 g/l.
 3. Acomposition according to claim 2, wherein the concentration of component(B) is from 0.1 to 3 g/l.
 4. A composition according to claim 3 that hasa pH value from 2.0 to 5.0.
 5. A composition according to claim 2 thathas a pH value from 2.0 to 5.0.
 6. A composition according to claim 1that has a pH value from 2.0 to 5.0.
 7. A process for forming aprotective coating, which contains manganese and at least one oftitanium and zirconium, on an aluminum or aluminum alloy substratesurface, said process comprising an operation of contacting saidsubstrate surface with a composition according to claim 4 at atemperature and for a time interval that are sufficient to result information over said substrate of said protective coating that containsan amount of manganese and an amount of a total of titanium andzirconium, said protective coating being sufficiently adherent to saidsubstrate surface that it is not removed by being rinsed with water at atemperature of 25° C.
 8. A process according to claim 7 wherein saidtemperature is in a range from 20 to 80° C. and said time is in a rangefrom 1 to 120 seconds.
 9. A process according to claim 8 wherein theprotective coating formed has a mass per unit area that is from 5 to 500mg/m².
 10. A process according to claim 9 wherein said mass per unitarea includes from 5 to 300 mg/m² of manganese and from 3 to 100 mg/m²of a total of titanium and zirconium.
 11. A process according to claim10, wherein the amount of manganese in said protective coating has aratio to the amount of a total of zirconium and titanium in the sameprotective coating that is from 0.2 to 5.0:1.0.
 12. An article ofmanufacture comprising a substrate consisting of aluminum or aluminumalloy and a protective coating thereover, said protective coatingcomprising from 5 to 300 mg/m² of manganese and from 3 to 100 mg/m² of atotal of titanium and zirconium, said protective coating further beingsufficiently adherent to said substrate surface that is not removed bybeing rinsed with water at a temperature of 25° C.
 13. An article ofmanufacture according to claim 12 wherein the protective coating formedhas a mass per unit area that is from 5 to 500 mg/m².
 14. An article ofmanufacture according to claim 13 wherein the amount of manganese insaid protective coating has a ratio to the amount of a total ofzirconium and titanium in the same protective coating that is from 0.1to 20:1.0.
 15. A process for forming a protective coating, whichcontains manganese and at least one of titanium and zirconium, on analuminum alloy substrate surface, said process comprising an operationof contacting said substrate surface with a composition according toclaim 1 at a temperature and for a time interval that are sufficient toresult in formation over said substrate of said protective coating thatcontains an amount of manganese and an amount of a total of titanium andzirconium, said protective coating being sufficiently adherent to saidsubstrate surface that it is not removed by being rinsed with water at atemperature of 25° C.
 16. A process according to claim 15, wherein saidtemperature is in a range from 20 to 80° C. and said time is in a rangefrom 1 to 120 seconds.
 17. A process according to claim 16, wherein theprotective coating formed has a mass per unit area that is from 5 to 500mg/m².
 18. A process according to claim 17, wherein said mass per unitarea includes from 5 to 300 mg/m² of manganese and from 3 to 100 mg/m²of a total of titanium and zirconium.
 19. A process according to claim18, wherein the amount of manganese in said protective coating has aratio to the amount of a total of zirconium and titanium in the sameprotective coating that is from 0.1 to 20:1.00.